Check Device

The tool works by sending SMS to SIM800L with a specific sequence of characters.For example, to turn on relay 1, use the “Relay 1 ON” command, and to turn it off, use the “Relay 1 OFF” command. For the other relays, almost the same commands, with the exception of the sequence number of each relay that you want to influence. After automatically sending a message, the SIM800 will send a response in the form of a message about the status of each SIM card.